A subsea wellhead assembly installed at the sea floor may be in water thousands of feet deep. During completion and certain production operations, components from a floating platform are lowered from the platform to engage the subsea wellhead assembly. Often, the components will have seals that are subject to being damaged while lowering through openings in the floating platform and also while being stabbed into the wellhead assembly. A remote operated vehicle (“ROV”) may be used to help stab and guide the component being lowered from the surface vessel.
For example, one component comprises a tieback connector. A tieback connector connects a production riser between a subsea wellhead housing and the surface production platform. Typically a surface production tree locates at the upper end of the production riser on the production platform. A tieback connector normally has an tubular body with a lower end that stabs into the bore of a casing hanger. A seal on the lower end of the tieback body engages a seal surface in the casing hanger. The tieback connector has locking elements that lock into a profile in the wellhead housing. Care must be taken during running of the tieback connector to avoid damage to the seal, particularly while entering the bore of the wellhead housing. It is known to install a sleeve over the seal prior to lowering the tieback connector through the platform. However, an ROV must be employed to remove the sleeve prior to stabbing the tieback connector into the wellhead housing.
Casing hangers in subsea wells often will have a lockdown mechanism to resist upward movement of the casing hanger that may occur due to thermal growth during production. The lockdown member engages an upper end of the casing hanger and a grooved profile in the bore of the wellhead housing. Normally, installing the lockdown member requires an extra trip to be made with a running tool, costing valuable rig time.